The mechanism of transcriptional termination of RNA polymerase II in adenovirus type 2 (Ad-2) infected Hela cells will be investigated. Our approach will use the techniques of Molecular Biology to determine the sites within the Ad-2 genome which code for transcriptional termination. First, the termination sites for the Ad-2 large late trnascript will be examined by RNA fingerprinting and DNA sequencing. We will study this transcription unit first because it is the best characterized eukaryotic RNA polymerase II transcript. Much work has been done to position its 3' termini on the Ad-2 physical map. Furthermore, it is known that the terminal nucleotides are never processed to mRNA and that they accumulate within the nucleus. Following the large late transcription unit, the protein XI and early region II 3' termini will be studied. Using UV target size analysis and RNA fingerprinting techniques, sequences beyond the 3' termini of the mRNA coded in these transcription units will be mapped. DNA sequences surrounding the termination sites will be compared for common sequences and structures. Premature termination sites within the large late transcript which can be enhanced by DRB (5,6-dichloro-1 beta-D-ribofuranosylbenzimidazole) will be examined for similarities between themselves and the regular termination site. The importance of premature transcripitional termination as a method of regulation of gene expression is well known in the bacterial tryptophan gene. Now we wish to examine transcriptional termination as a possible method of regulation of eukaryotic gene expression.